The present invention relates to an improved control handle for a bidirectional steerable catheter.
Electrode catheters have been in common use in medical practice for many years. They are used to stimulate and map electrical activity in the heart and to ablate sites of aberrant electrical activity.
In use, the electrode catheter is inserted into a major vein or artery, e.g., femoral artery, and then guided into the chamber of the heart which is of concern. Within the heart, the ability to control the exact position and orientation of the catheter tip is critical and largely determines how useful the catheter is.
Steerable catheters are generally well-known. For example, U.S. Pat. No. RE 34,502 describes a catheter having a control handle comprising a housing having a piston chamber at its distal end. A piston is mounted in the piston chamber and is afforded lengthwise movement. The proximal end of the catheter body is attached to the piston. A puller wire is attached to the housing and extends through the piston and through the catheter body. The distal end of the puller wire is anchored in the tip section of the catheter. In this arrangement, lengthwise movement of the piston relative to the housing results in deflection of the catheter tip section.
The design described in RE 34,502 is generally limited to a catheter having a single puller wire. If a bidirectional catheter is desired, i.e., a catheter that can be deflected in more than one direction without rotating the catheter body, more than one puller wire becomes necessary. When two puller wires are used, however, it is undesirable for both wires to be moved simultaneously. The handle design disclosed in RE 34,502 is not suitable for a two puller wire system. Accordingly, a need exists for a control handle capable of independently moving each of two puller wires but preventing simultaneous movement of the puller wires.
The invention is directed to a steerable catheter having two puller wires and a control handle for manipulating the puller wires, and more preferably a bidirectional steerable catheter. In one embodiment, the catheter comprises an elongated, flexible tubular catheter body having proximal and distal ends and a lumen extending therethrough and a control handle at the proximal end of the catheter body. The control handle comprises a handle housing having a generally hollow interior and fixedly attached, either directly or indirectly to the catheter body; a piston slidably mounted in the handle housing and having proximal and distal ends; and a pulley fixedly attached, either directly or indirectly to the handle housing at a location proximal to the proximal end of the piston. A first puller wire is provided having a distal end fixedly attached in the distal end of the catheter body and a proximal end anchored to the piston. A second puller wire is provided having a distal end fixedly attached in the distal end of the catheter body. The second puller wire extends through the catheter body, into the handle, and around the pulley, and the proximal end of the second puller wire is anchored to the piston. By this design, simultaneous deflection of both puller wires can be avoided.